The present invention relates to gas lasers, and particularly to gas lasers which are compact in size.
Over the past decade, advances in the art have resulted in a reduction in the size of typical gas lasers from diameters on the order of several inches to diameters of about an inch. However, such reduction in size has unfortunately caused a concomitant reduction in the operating life of the laser. In general, it has been found that laser operating lifetimes are an inverse function of laser diameter.
At the present time, reduced operating lifetimes have limited minimum laser size to diameters on the order of about 3/4 to 1 inch. Although lasers with diameters of less than 3/4 inch will operate, the lifetimes of such lasers are so short as to render them impractical for commercial purposes.
Laser failure ordinarily results from a phenomena commonly referred to as "cathode sputtering" which causes occlusion of the resonator mirrors by deposition of metal from the laser cathode, and/or causes detrimental changes in the operating characteristics of the laser. Thus, there is a need in the art for a gas laser which reduces cathode sputtering so as to extend the laser operating life.
Compact gas lasers are advantageous for a variety of applications, such as gun sites, hand-held bar code readers, and hand-held laser pointers. In addition, a miniaturized laser, if adapted to operate at a wavelength of about 1.5 microns, would be particularly attractive for optical fiber communications, since, as is well known, typical optical fibers exhibit lowest attenutation during transmission at a wavelength of about 1.5 microns.